A285809 Primes equal to a centered triangular number plus 1.

2, 5, 11, 47, 137, 167, 317, 461, 761, 977, 1307, 1787, 2111, 2711, 3677, 4457, 5861, 7247, 7457, 9011, 10211, 13397, 15761, 17987, 22511, 23627, 43607, 45677, 54437, 56747, 58511, 61511, 63347, 65837, 66467, 79697, 82487, 88211, 90407, 93377, 97157, 108947

Offset

1,1

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Prog

(PARI) cpg(m, n) = m*n*(n-1)/2+1 \\ n-th centered m-gonal number
maxk=600; L=List(); for(k=1, maxk, if(isprime(p=cpg(3, k) + 1), listput(L, p))); Vec(L)

Crossrefs

Cf. A000040, A005448, A285810, A285811, A285812.

Sequence in context: A160859 A106887 A236044 * A089609 A362525 A277041

Adjacent sequences: A285806 A285807 A285808 * A285810 A285811 A285812

Keyword

nonn

Author

Colin Barker, Apr 27 2017

Status

approved